1. Field of the Invention
The present invention relates generally to cross-oriented films, and more particularly to a method and apparatus for the formation of such type of films from a thermoplastic synthetic resin.
2. Description of the Prior Art
Heretofore, a uniaxially oriented film such as for example, an oriented tape, has exhibited the disadvantage of tearing easily in a lateral direction, while a biaxially oriented film has various problems associated with its production speed, as well as orientation magnification, in the case of a tubular method, and with expensive and complex methods and apparatus for gripping both ends of the film in the case of a tenter method. In addition, biaxially oriented films also generally exhibit poorer mechanical properties, with lower orientation magnification, than is obtained with uniaxially oriented films.
A method of laminating a uniaxially oriented film with the orientations disposed perpendicular to each other is generally known, as is a method which includes the steps of supplying a uniaxially oriented film at an inclined angle so as to enable it to be wound in a spiral fashion and then laminating the same in a flat manner so as to utilize the features of the uniaxially oriented film and also for compensating for the disadvantages thereof. These materials are not however, commercially acceptable at the present time because of the undesirable exposure of the seam within the finished film.